WASHINGTON (CNN) -- Reversing a position it defended for more than a year, the Bush administration announced Wednesday that it has begun getting court approval before eavesdropping on the communications of suspected terrorists or their associates.

The Justice Department notified Congress that a court set up to specialize in wiretapping would oversee its "terrorist surveillance program," which the administration has said could operate without judicial review. Critics said that violated the Foreign Intelligence Surveillance Act of 1978, which set up a special court to review wiretap applications in intelligence cases.

"The president is committed to using all lawful tools to protect our nation from the terrorist threat, including making maximum use of the authorities provided by FISA and taking full advantage of developments in the law," Gonzales wrote.

Neither Gonzales nor Justice Department officials disclosed details of the rules set by the court, arguing that details were classified. But Gonzales said President Bush would no longer authorize the existing program, which administration officials said was necessary because the court set up under FISA was too slow to respond to new terrorist threats. (Read Gonzales' letter to the Senate Judiciary Committee)

"To save American lives, we must be able to act fast and to detect these conversations so we can prevent new attacks," Bush said in December 2005.

Gonzales to face Senate committee

The administration's reversal comes a day before Gonzales was scheduled to appear before the Senate Judiciary Committee. Its chairman, Vermont Democrat Patrick Leahy, said he welcomed the decision.

"As I pointed out for some time, and as other senators on both sides of the aisle pointed out, that was, at the very best, of doubtful legality," Leahy said. He said surveillance was needed to prevent terrorist attacks, "but we can and we should do it in ways that protect the basic rights of all Americans."

House Speaker Nancy Pelosi, D-California, called the move "a long-overdue recognition" that existing laws can protect the country.

"Although the judge's order announced today needs to be reviewed thoroughly, the fact that the president will no longer be authorizing unilaterally intrusive surveillance of people in the United States is good news," Pelosi said in a written statement.

Democratic Rep. Silvestre Reyes of Texas, the chairman of the House Intelligence Committee, called the decision "welcome news, if long overdue."

"It proves that this surveillance has always been possible under the Foreign Intelligence Surveillance Act and that there was never a good reason to evade the law," Reyes said in a written statement.

The government now will ask the court to approve surveillance requests for 90 days, after which it must seek renewed permission. Justice Department officials said the court issued more than one order governing the program, but they refused to provide details of the still-classified program.

The officials also refused to comment on how the procedures could be implemented without damaging national security, as top administration figures insisted.

Gonzales wrote that the administration has been working with the court for two years to bring the program under FISA, even as it defended the program and resisted calls for greater oversight. But the White House dismissed suggestions that the announcement was influenced by political concerns.

"It's an example of a case where we take hits for doing what's right rather than getting credit for what seems to be expedient," White House spokesman Tony Snow said.

Bush authorized the National Security Agency to eavesdrop on calls to or from people suspected of having ties to al Qaeda shortly after the terror network's September 2001 attacks on New York and Washington. The program remained secret for four years, and ignited a controversy once it was disclosed.

Sen. Arlen Specter, then chairman of the Senate Judiciary Committee, said FISA "flatly prohibits" electronic eavesdropping without a judge's permission. A federal judge ruled the program unconstitutional in July.

ACLU skeptical of motives

The American Civil Liberties Union, which led the court challenge to the program, called the decision to submit the program to the FISA court "an effort to avoid judicial and congressional scrutiny."

"The legality of this unprecedented surveillance program should not be decided by a secret court in one-sided proceedings," said Ann Beeson, the lead attorney in the group's lawsuit. The group said it would urge the FISA court to release more information about its new orders, which Gonzales said were issued January 10.

Specter, now the Judiciary Committee's ranking Republican, said he wants to see more detail about how the program will now be run.

"I think we need to know more about the procedures on the determination of probable cause, whether it is on individualized warrants or it is a group program," he said. "And we will need to know more about the determination of the individual being an agent of al Qaeda."

A senior Justice Department official, who spoke on condition of anonymity because of the sensitivity of the information, said the department still believes the 1978 law should be modified to account for advances in electronic communication. Wednesday's announcement will "take some political heat off the debate," he said.

"These orders allow us to do the same thing that we've been doing, but we will be operating under the orders we've obtained from a FISA judge," the official said.